Recognition of the individuality of foot support problems is implicit in medically developed orthopedic shoes and critically desirable in shoes for recreational and athletic endeavors. Although some attempts have been made to make individually adjustable supports for shoes more amenable to a mass-production process, devices currently available have to be painstakingly fitted to each deformity for orthopedic use and lack the capability of being accommodative and dynamically adaptive during any use.
Biomechanical studies of the human gait cycle have focused attention on the desirability of providing additional cushioning and support at certain critical areas of the foot. One theory, e.g., would require a foot support device to provide an extra fraction of a second of support to the heel in order to reduce the shock of the "strike" portion of the gait cycle. Moreover, these studies have indicated that the weight of a foot cushioning device plays a very significant part in determining the overall effectiveness of the device. For these and other reasons, interest has continued over the years in the development of a practical, effective pneumatic cushion.
The concept of having the sole portion of a shoe fabricated so as to define a hollow inflatable cavity therein has long been disclosed, but without commercial realization. U.S. Pat. Nos. 508,034 (Moore), 572,887 (Gallagher), 580,501 (Mobberley), 1,056,426 (Kenny), 1,148,376 (Gay), 1,304,915 (Spinney), 1,498,838 (Harrison, Jr.), 1,639,381 (Manelas), 2,605,560 (Gouabault), 2,863,230 (Cortina), 3,120,712 (Menken), 3,785,069 (Brown), 4,012,854 (Berend), British Pat. No. 7507 (Crawford), British Pat. No. 358,205 (Marling), French Pat. No. 996,111 (Milonas), all disclose boots or shoes with a sole having a cavity defined therein for supporting a pneumatic cushion. Further, U.S. Pat. Nos. 508,034 (Moore), 1,010,187 (Scott), 1,148,376 (Gay), and 2,682,712 (Owsen) disclose inflating openings or valve arrangements disposed in cooperative association with a cavity defined within the shoe. Yet further, U.S. Pat. No. 3,871,117 (Richmond) discloses a shoe wherein energy supplied by the movement of the wearer in walking pumps a cooling fluid through a cavity disposed within a sole and a tubular cooling fin arrangement in communication therewith disposed along the sides of the shoe upper.
Generally, such prior attempts at providing pneumatic cushioning of the foot have involved a single fluid receiving bladder, tubular in shape, which was supposed to provide cushioned support to the entirety of the wearer's foot. Although providing some measure of cushioned support, such tubular members, or bladders, have had a number of problems. For example, with shoes containing a single fluid receiving cavity the wearer must become accustomed to a rock and sway motion. That is, with any weight shift while wearing such equipped shoes the wearer will rock side-to-side and sway front-to-back as the fluid is continually displaced. Other problems were in deflation and replacement and in the size and weight of the shoes necessary to contain such bladders. Moreover, even the best concepts of inflatable pneumatic cushions had limited orthopedic value in that they could not effectively be adapted to truly cushion injured or diseased feet while at the same time being practical for normal walking endeavors.
It would be advantageous to provide a pneumatically cushioned shoe which does not alter the structural integrity of the sole or heel portions thereof nor add any significant weight which would have to be lifted by the wearer. Further, to gain additional orthopedic and comfort advantages provided by walking on a volume of pressurized fluid, it would be advantageous to provide a foot support member which could be made according to a preselected design to contact only certain portions of the foot dependent upon the nature of the wearer's orthopedic concerns. Such a shoe or a foot support member should most advantageously be lightweight, and readily producible.
Except as discussed herein, in none of the art cited above does it appear possible to easily replace or clean a bladder (if one were provided) or to repair a rupture of the fluid containment volume. Accordingly, these shoes once rendered nonfunctional would ordinarily be discarded. Although Scott, U.S. Pat. No. 1,010,187, shows access to the bladder may be gained by unlacing a portion of the shoe located at the heel and thereof and withdrawing the bladder through the heel portion and Owsen, U.S. Pat. No. 2,682,712, describes the need for unlatching clasps located in the toe and heel portions of the shoe to remove the lower sole thereby gaining access to the bladder, these expedients are believed to be cumbersome and non-advantageous in practice. Thus, it would be advantageous to provide a shoe with an easily and expeditiously replaceable bladder disposed therein. Additionally, it would be advantageous to provide ready access to the bladder to facilitate replacement or repair as warranted by orthopedic considerations, among others. Providing such an inflatable member in the shoe of the wearer would, in addition to providing the advantage of walking on a pneumatic layer of fluid, such as, for example, air, insulate the foot of the wearer from cold and heat. Yet further, wearer comfort in any field of endeavor can be enhanced through the utilization of the shoe having an inflatable support member disposed therein.